So I have this immediate problem: a PGXS build of a module, specifically an hstore transform for a non-core PL, is much harder than it should be because it has no way to get at hstore.h since that file is never installed anywhere.
Should that be changed?
I think there's agreement in the thread that it should, and strong +1 from me.
I just wanted to pipe up with something Petr pointed out during pglogical development, which is that Pg offers a handy tool to help extensions link up with each other - find_rendezvous_variable(...) from dfmgr.c / fmgr.h .
It's a real shame it's not more visible in contrib/ examples and the docs. Any suggestions on where it should appear in the docs? Somewhere in extend.sgml, presumably.
You still need a header from the other extension to *use* it, but it provides a massively easier way to find a struct of API function pointers. Prior to using it, I had a hack where I dlopen()ed the other shared library directly, and I'd also trialled using the fmgr to call a 'returns internal' function to get the API pointers struct that way.
